I don't think he was a Ranger. He just was smart enough to surround himself with a lot of Rangers Powers. So he could give them to his proteges to protect whatever planet needed protecting. Which for thousands of years was Earth.

I think Zordon was the original White Ranger. But the powers were lost a long time ago when he got stuck in the Time Warp. He was able to recreate them with Alpha in "White Light". So Tommy would still be able to help the team against Zedd as White Ranger.

I think Zordon, Rita, Zedd, and Divatox were all Rangers at one point. Something happened to corrupt the bottom three. Which led to the end of Zordon's run as a Ranger and him being stuck in a time warp.

Perhaps Ecliptor was the Fifth Ranger of that team and the one responsible for selling them out to Dark Spector. He was mortally wounded during the last battle and lost his memories. Spector had him rebuilt into an evil foot soldier. This is why Zordon's Wave vaporized him instead of purified. Despite his true fatherly love for Karone.

Very interesting ideas. I could see Ecliptor's guilt being so great ( more of a feeling since you said his memories were gone) that they eventually magically became a a separate enity that became Darkonda. Hench who Ecliptor always believed him to be a traitor. When he is really just hating the part of himself that betrayed his team.